Oil burner



F. WOLFF OIL BURNER Sept. 25, 1934.

Filed Feb. 3, 1932 Patented Sept. 25, 1934 UNITED STATES OIL BURNER.

Friedrich 'Wolfl', Berlin, Germany, assignor to the firm Selas Aktiengesellschaft, Berlin, Germany Application February 3, 1932, Serial No. 590,731

InGe

many February 23, 1931 2 Claims. (Cl. 158-76) The present invention relates to oil burners." More particularly the inventionrelates to oil burners the nozzles of which are formed with back suction openings and at which the heating oil is 5 drawn by suction through the air which promotes combustion.

It has previously been proposed to improve the fuel ignition at burners of the above named kind by utilizing the under-pressure. created by the fuel-air-mixture injected through the nozzle for exerting a sucking action on the hot furnace gases. For this purpose the nozzle of the burner has been arranged in the combustion space proper.

According to the present invention a still better effect is obtained by arranging the fuel nozzle in such a manner that it is surrounded by an annular space which is closed off from the atmosphere. This space may for instance be formed by surrounding the mouth piece of the fuel injector with a tubular member which is of greater diameter than the mouthpiece and one end of which is connected to the burner structure whereas the other end is directly connected to the ad- I jacent parts of the furnace for instance to the refractory chamotte lining of the same. The

efiect of this arrangement is, that only hot flame gases deflected from the outer burning mantle of the ignited fuel cone are sucked back into the mouthpiece, whereby the caping fuel mixture is reduced and the. temperature of the same is raised, so that the inflamma- -bility of the fuel is considerably improved independently of the burner output. Further the tearing-off of the burner flame is prevented even at high oil" consumption. The velocity of flow of the fuel mixture may be still more reduced by arranging 'a cylindrical section in the conical flame channel in the refractory lining of the furnace.

40 When the flame jet impinges against this cylinrangement.

flow velocity of the es- 1 denotes an oil supply pipe through which the fuel oil is fed to an oil tube 2 which terminates in an oil nozzle 3. Through the main air feed conduit 4 and a channel 5 fresh or primary air is admitted to the air tube 6, which is arranged on the outside of the oil tube 2, coaxially to the same. The secondary air is also derived from the main air conduit 4 and is conducted to the mouthpiece or main burner nozzle 8 through a throttle valve 7. As indicated in Fig. 1 of the drawing the mouthpiece or main burner nozzle 8 surrounds the nozzle parts of the tubes 2 and 6. The conically widened outer end 9 of the mouth piece 8 is equipped with apertures or slots 10 on which a sucking action is exerted by the fuel passing through the mouthpiece. The fuel nozzle 8 is sur rounded by a tubular member 11 which is ar- 'ranged in spaced relation to the nozzle to form an annular chamber 17 therebetween, the rear end of which chamber is closed against access of' atmospheric air. One end of the member 11 is connected to the burner casing and the other end of said member is connected to the furnace wall in such relation to the conical flame passage 12 in the chamotte stone 13, that only hot flame gases are sucked back into the main burner nozzle through the openings 10. These flame gases, which consist of particles separated from the ignited jet of oil-air-mixture in the furnace chamber 14, will, when sucked back through the 30 said openings; heat the outer mantle face of the Jet of fuel mixture,simultaneously reducing the flow velocity of the particles forming this outer mantle face. Hereby the necessary inflammability is maintained independently of the temperature of the burner and of the amount of fuel mixture flowing into the furnace.

The fuel or flame, channel in the chamotte stone 13 is composed of three sections, namely an outer conical section 12, an intermediate cylindrical section 15 and an inner conical section 16, which opens into the furnace chamber 14. The cylindrical'section 15 acts as a baflle on the fuel cone and causes eddies to be set up in the outer layers of same, whereby the flow velocity is further reduced and the inflammability of the fuel is increased.

It will be understood, that the invention is applicable not only to oil burners but also to burners consuming other liquid fuels.

I claim:--- 1. An oil burner comprising a main nozzle open at both ends, means to supply secondary air to the rear end of said main nozzle, a nozzle arranged 5 to discharge oil into said main'nozzle through the rear end thereof, a primary air discharging nozzle in which the oil discharging nozzle is coaxially arranged, said primary air discharging nozzle also discharging through the rear end of the main nozzle and operating to supply oil to the oil nozzle by suction, and a member around the main burner nozzle closed at the rear end thereagainst to prevent the intake of atmospheric air and being otherwise spaced from the main nozzle so that a forwardly opening chamber is formed therearound, said main burner nozzle having a gas opening in its wall establishing communication between said chamber and the interior of said main nozzle.

- 2. An oil burner as claimed in claim 1, including a valved duct leading to the rear end oi the main burner nozzle for the supply of secondary air thereto and a duct leading from the first named duct to the primary air discharging nozzle.

FRIEDRICH WOLFE.

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